Displaying publications 1 - 20 of 85 in total

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  1. Suria, M. S., Adlin Azlina, A. K., Mohd Afendy, A. T., Zamri, I.
    MyJurnal
    Shiga toxin-producing E. coli (STEC) is an important foodborne pathogen causing diarrhea, hemorrhagic colitis and hemolytic-uremic syndrome in humans. STEC is an implicated in the vast majority of outbreaks, widely via consumption of STEC contaminated beef, as important vehicle of transmission of this organism to human. The E. coli O157:H7 serotype is traditionally identified by serological identification of the somatic antigen (O157) and structural flagella (H7). In this study, the bacteria were identified as STEC serotype O157:H7 with three primer pairs that amplified fragments of secD, rfbE and fliC genes in PCR assays. These primer pairs specifically amplified different sizes of target genes: a 244bp region of the E. coli diagnostic marker gene (secD); a 317bp region of the O157 lipopolysacharide (LPS) gene (rfbE); and a 381bp region of the H7 flagellin gene (fliC). The singleplex, duplex and triplex PCR assay developed in this study have a sensitivity limit at 2.8 x 103, 2.8 x 105 and 2.8 x 107 CFU/ml of E. coli O157:H7, respectively. Sensitivity to detect trace amount of E. coli O157:H7 DNA was reduced as the number of primer used was increased for competing to the same DNA template.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction
  2. Zeti Norfidiyati Salmuna, Murnihayati Hassan, Habsah Hasan, Zakuan Zainy Deris
    MyJurnal
    Carpanenamase-producing Enterobacteriaceae (CPE) has emerged as a threat to hospitalized patients. Phenotypic test such as Modified hodge test was less sensitive and specific especially to detect blaNDM-1 which is the most predominant genotype in this region. Nucleic acid amplification technology offers improved specificity and sensitivity. Failed amplification due to the presence of inhibitors is a limitation. In this study, we tried to use previous method described by Villumseen et al with some modification using another DNA extraction kit. Methods: Ten mls of sterile whole blood taken from nearly expired blood bag from blood bank was spiked with 200 μl of 0.5mcFarland bacterial suspension from thirty-six confirmed isolates of blaNDM-1 carbapenamase-producing Klebsiella pneumoniae in an aerobic Bactec Plus and incubated until the growth was detected. The blood specimen was subjected to DNA extraction method using Macherey-Nachel, Nucleospin® Blood QuickPure followed with multiplex PCR. Results: Out of the 36 isolates, 12 isolates revealed blaNDM-1 , 9 isolates revealed blaNDM-1 and blaOXA-48, 7 isolates revealed blaNDM-1, blaVIM and blaKPC genotypes that were amplified at cycle threshold of less than 30. Another 8 isolates could not pick up any genotypes possibly due to pipetting error as all the internal control were amplified. Eight true negative gram negative isolates underwent same procedure and none amplified at a cycle threshold less than 30. Conclusion: This modified method was proved to give a high yield of CPE genotypes with the cycle threshold was set at less than or equal to 30 and able to overcome the presence of PCR inhibitors.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction
  3. Tang TH, Ahmed SA, Musa M, Zainuddin ZF
    World J Microbiol Biotechnol, 2013 Dec;29(12):2389-95.
    PMID: 23807412 DOI: 10.1007/s11274-013-1407-0
    Although the multi-copy and specific element IS6110 provides a good target for the detection of Mycobacterium tuberculosis complex by PCR techniques, the emergence of IS6110-negative strains suggested that false negative may occur if IS6110 alone is used as the target for detection. In this report, a multiplex polymerase chain reaction (mPCR) system was developed using primers derived from the insertion sequence IS6110 and an IS-like elements designated as B9 (GenBank accession no. U78639.1) to overcome the problem of detecting negative or low copy IS6110 containing strains of M. tuberculosis. The mPCR was evaluated using 346 clinical samples which included 283 sputum, 19 bronchial wash, 18 pleural fluid, 9 urine, 7 CSF, 6 pus, and 4 gastric lavage samples. Our results showed that the sensitivity (93.1 %) and specificity (89.6 %) of the mPCR system exceeds that of the conventional method of microscopy and culture. The mPCR assay provides an efficient strategy to detect and identify M. tuberculosis from clinical samples and enables prompt diagnosis when rapid identification of infecting mycobacteria is necessary.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction*
  4. Hossain MA, Ali ME, Abd Hamid SB, Asing, Mustafa S, Mohd Desa MN, et al.
    J Agric Food Chem, 2016 Aug 17;64(32):6343-54.
    PMID: 27501408 DOI: 10.1021/acs.jafc.6b02224
    Beef, buffalo, and pork adulteration in the food chain is an emerging and sensitive issue. Current molecular techniques to authenticate these species depend on polymerase chain reaction (PCR) assays involving long and single targets which break down under natural decomposition and/or processing treatments. This novel multiplex polymerase chain reaction-restriction fragment length polymorphism assay targeted two different gene sites for each of the bovine, buffalo, and porcine materials. This authentication ensured better security, first through a complementation approach because it is highly unlikely that both sites will be missing under compromised states, and second through molecular fingerprints. Mitochondrial cytochrome b and ND5 genes were targeted, and all targets (73, 90, 106, 120, 138, and 146 bp) were stable under extreme boiling and autoclaving treatments. Target specificity and authenticity were ensured through cross-amplification reaction and restriction digestion of PCR products with AluI, EciI, FatI, and CviKI-1 enzymes. A survey of Malaysian frankfurter products revealed rampant substitution of beef with buffalo but purity in porcine materials.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction/methods*
  5. Lee HG, William T, Menon J, Ralph AP, Ooi EE, Hou Y, et al.
    BMC Infect Dis, 2016 06 16;16:296.
    PMID: 27306100 DOI: 10.1186/s12879-016-1640-x
    BACKGROUND: Central nervous system (CNS) infections are a significant contributor to morbidity and mortality globally. However, most published studies have been conducted in developed countries where the epidemiology and aetiology differ significantly from less developed areas. Additionally, there may be regional differences due to variation in the socio-economic levels, public health services and vaccination policies. Currently, no prospective studies have been conducted in Sabah, East Malaysia to define the epidemiology and aetiology of CNS infections. A better understanding of these is essential for the development of local guidelines for diagnosis and management.

    METHODS: We conducted a prospective observational cohort study in patients aged 12 years and older with suspected central nervous system infections at Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia between February 2012 and March 2013. Cerebrospinal fluid was sent for microscopy, biochemistry, bacterial and mycobacterial cultures, Mycobacterium tuberculosis polymerase chain reaction (PCR), and multiplex and MassCode PCR for various viral and bacterial pathogens.

    RESULTS: A total of 84 patients with clinically suspected meningitis and encephalitis were enrolled. An aetiological agent was confirmed in 37/84 (44 %) of the patients. The most common diagnoses were tuberculous meningitis (TBM) (41/84, 48.8 %) and cryptococcal meningoencephalitis (14/84, 16.6 %). Mycobacterium tuberculosis was confirmed in 13/41 (31.7 %) clinically diagnosed TBM patients by cerebrospinal fluid PCR or culture. The acute case fatality rate during hospital admission was 16/84 (19 %) in all patients, 4/43 (9 %) in non-TBM, and 12/41 (29 %) in TBM patients respectively (p = 0.02).

    CONCLUSION: TBM is the most common cause of CNS infection in patients aged 12 years or older in Kota Kinabalu, Sabah, Malaysia and is associated with high mortality and morbidity. Further studies are required to improve the management and outcome of TBM.

    Matched MeSH terms: Multiplex Polymerase Chain Reaction
  6. George E, Teh LK, Tan J, Lai MI, Wong L
    Pathology, 2013 01;45(1):62-5.
    PMID: 23222244 DOI: 10.1097/PAT.0b013e32835af7c1
    AIMS: Classical carriers of β-thalassaemia are identified by a raised HbA2 level. Earlier studies indicated that the Filipino β-deletion has high raised HbA2 levels. The introduction of automated high performance liquid chromatography (HPLC) for thalassaemia screening is an important advance in technology for haematology laboratories. The BioRad Variant II Hb analyser is a common instrument used to quantify HbA2 levels in thalassaemia screening. This study aimed to determine HbA2 levels in carriers of Filipino β-mutation using the BioRad Variant II Hb analyser.

    METHODS: The Filipino β-deletion was identified using gap-polymerase chain reaction (PCR) in the parents of transfusion dependent β-thalassaemia patients who were homozygous for the Filipino β-deletion in the indigenous population of Sabah, Malaysia. Hb subtypes were quantified on the BioRad Variant II Hb analyser. Concurrent α-thalassaemia was identified by multiplex gap-PCR for deletions and amplification refractory mutation system (ARMS)-PCR for non-deletional mutations.

    RESULTS: The mean HbA2 level for Filipino β-thalassaemia trait was 5.9 ± 0.47 and with coinheritance of α-thalassaemia was 6.3 ± 0.44 (-α heterozygous) and 6.7 ± 0.36 (-α homozygous). The HbA2 levels were all >4% in keeping with the findings of classical β-thalassaemia trait and significantly higher than levels seen in non-deletional forms of β-thalassaemia.

    CONCLUSION: The HbA2 level measured on the BioRad Variant II Hb analyser was lower than the level in the first description of the Filipino β-thalassaemia. β-thalassaemia trait with coinheritance of α-thalassaemia (-α) is associated with significantly higher HbA2 level.

    Matched MeSH terms: Multiplex Polymerase Chain Reaction
  7. Thung TY, Radu S, Mahyudin NA, Rukayadi Y, Zakaria Z, Mazlan N, et al.
    Front Microbiol, 2017;8:2697.
    PMID: 29379488 DOI: 10.3389/fmicb.2017.02697
    The aim of the present study was to investigate the prevalence of Salmonella spp., Salmonella Enteritidis and Salmonella Typhimurium in retail beef from different retail markets of Selangor area, as well as, to assess their pathogenic potential and antimicrobial resistance. A total of 240 retail beef meat samples (chuck = 60; rib = 60; round = 60; sirloin = 60) were randomly collected. The multiplex polymerase chain reaction (mPCR) in combination with the most probable number (MPN) method was employed to detect Salmonella spp., S. Enteritidis and S. Typhimurium in the meat samples. The prevalence of Salmonella spp., S. Enteritidis and S. Typhimurium in 240 beef meat samples were 7.50, 1.25, and 0.83%, respectively. The microbial loads of total Salmonella was found in the range of <3 to 15 MPN/g. Eight different serovars of Salmonella were identified among the 23 isolates, and S. Agona was the predominant serovar (26.09%). Interestingly, all the Salmonella isolates were resistant to penicillin, erythromycin and vancomycin, but the sensitivity was observed for tetracycline, gentamicin and amoxicillin/clavulanic acid. All 23 isolates were resistant to at least three antibiotics. Two S. Typhimurium isolates (8.70%) exhibited the highest multiple antibiotic resistance (MAR) index value of 0.56 which shown resistance to nine antibiotics. PCR analysis of virulence genes showed that all Salmonella isolates (100%) were positive for the invA gene. Meanwhile, pefA was only identified in S. Enteritidis and S. Typhimurium. The findings in this study indicate that retail beef products tested were widely contaminated with multi-drug resistant (MDR) Salmonella and various virulence genes are present among the isolated Salmonella serovars.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction
  8. Thanh TT, Anh NT, Tham NT, Van HM, Sabanathan S, Qui PT, et al.
    Virol J, 2015 Jun 09;12:85.
    PMID: 26050791 DOI: 10.1186/s12985-015-0316-2
    BACKGROUND: Hand foot and mouth disease (HFMD) is a disease of public health importance across the Asia-Pacific region. The disease is caused by enteroviruses (EVs), in particular enterovirus A71 (EV-A71). In EV-A71-associated HFMD, the infection is sometimes associated with severe manifestations including neurological involvement and fatal outcome. The availability of a robust diagnostic assay to distinguish EV-A71 from other EVs is important for patient management and outbreak response.

    METHODS: We developed and validated an internally controlled one-step single-tube real-time RT-PCR in terms of sensitivity, linearity, precision, and specificity for simultaneous detection of EVs and EV-A71. Subsequently, the assay was then applied on throat and rectal swabs sampled from 434 HFMD patients.

    RESULTS: The assay was evaluated using both plasmid DNA and viral RNA and has shown to be reproducible with a maximum assay variation of 4.41 % and sensitive with a limit of detection less than 10 copies of target template per reaction, while cross-reactivity with other EV serotypes was not observed. When compared against a published VP1 nested RT-PCR using 112 diagnostic throat and rectal swabs from 112 children with a clinical diagnosis of HFMD during 2014, the multiplex assay had a higher sensitivity and 100 % concordance with sequencing results which showed EVs in 77/112 (68.8 %) and EV-A71 in 7/112 (6.3 %). When applied to clinical diagnostics for 322 children, the assay detected EVs in throat swabs of 257/322 (79.8 %) of which EV-A71 was detected in 36/322 (11.2 %) children. The detection rate increased to 93.5 % (301/322) and 13.4 % (43/322) for EVs and EV-A71, respectively, when rectal swabs from 65 throat-negative children were further analyzed.

    CONCLUSION: We have successfully developed and validated a sensitive internally controlled multiplex assay for rapid detection of EVs and EV-A71, which is useful for clinical management and outbreak control of HFMD.

    Matched MeSH terms: Multiplex Polymerase Chain Reaction/methods*; Multiplex Polymerase Chain Reaction/standards
  9. Ling, S., Noramirah, R., Abidatul, A.A., Nurfarhanah, N.M.J., Noor-Azira, A.M., Jambari, N.N., et al.
    Food Research, 2018;2(3):240-246.
    MyJurnal
    Foodborne illness is a global burden that impacts a country politically, economically and
    socio-economically. The severity of the burden can be unmeasurable as foodborne illness
    is often an underestimated problem. In order to enlighten the burden, appropriate food
    safety control measures should be taken. This study aimed to optimize a multiplex
    Polymerase Chain Reaction (mPCR) detection method to identify foodborne pathogens
    simultaneously. Six foodborne pathogens namely, Salmonella spp., Escherichia coli O157,
    Vibrio parahaemolyticus, Vibrio cholerae, Listeria monocytogenes and Campylobacter
    spp., were targeted in the mPCR detection method. Each mPCR parameter was tested and
    the outcome was analysed to obtain a successful mPCR protocol to detect the targeted
    foodborne pathogens. The amplified PCR products showed that the optimized mPCR
    protocol will be a potential rapid diagnostic tool in foodborne pathogen detection.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction
  10. Jacinta Santhanam, Mohd Hanif Jainlabdin, Ang LC, Tzar Mohd Nizam
    Sains Malaysiana, 2018;47:489-498.
    Invasive fungal infections (IFIs) have risen dramatically in recent years among high risk immunocompromised patients.
    Rapid detection of fungal pathogens is crucial to timely and accurate antifungal therapy. Two multiplex polymerase
    chain reaction (PCR) assays were developed to detect major fungal species that cause invasive infections and identify
    resistant species. Genus specific primers for Candida, Aspergillus, Fusarium and species specific primers for Candida
    glabrata, Candida krusei and Aspergillus terreus which are known to be clinically resistant species, were designed from
    the internal transcribed spacer (ITS) regions of ribosomal ribonucleic acid (rRNA) gene complex. Both assays were
    performed simultaneously to promote rapid detection of fungal isolates based on distinct amplicon sizes. Inclusion of the
    universal fungal primers ITS 1 and ITS 4 in the genus specific assay produced a second amplicon for each isolate which
    served to confirm the detection of a fungal target. The limit of detection for the genus specific assay was 1 nanogram
    (ng) deoxyribonucleic acid (DNA) for Aspergillus fumigatus and Candida albicans, 0.1 ng DNA for Fusarium solani, while
    the species-specific assay detected 0.1 ng DNA of A. terreus and 10 picogram (pg) DNA of C. krusei and C. glabrata. The
    multiplex PCR assays, apart from universal detection of any fungal target, are able to detect clinically important fungi
    and differentiate resistant species rapidly and accurately, which can contribute to timely implementation of effective
    antifungal regime.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction
  11. Jainlabdin MH, Batra A, Sánchez Paredes E, Hernández Hernández F, Fu G, Tovar-Torres J
    Sci Rep, 2019 10 11;9(1):14692.
    PMID: 31604994 DOI: 10.1038/s41598-019-51198-6
    Invasive candidiasis is one of the most common nosocomial fungal infections worldwide. Delayed implementation of effective antifungal treatment caused by inefficient Candida diagnosis contributes to its notoriously high mortality rates. The availability of better Candida diagnostic tools would positively impact patient outcomes. Here, we report on the development of a single-tube, dual channel pentaplex molecular diagnostic assay based on Multiplex Probe Amplification (MPA) technology. It allows simultaneous identification of C. auris, C. glabrata and C. krusei, at species-level as well as of six additional albicans and non-albicans pathogenic Candida at genus level. The assay overcomes the one-channel one-biomarker limitation of qPCR-based assays. Assay specificities are conferred by unique biomarker probe pairs with characteristic melting temperatures; post-amplification melting curve analysis allows simple identification of the infectious agent. Alerting for the presence of C. auris, the well-characterised multi-drug resistant outbreak strain, will facilitate informed therapy decisions and aid antifungal stewardship. The MPA-Candida assay can also be coupled to a pan-Fungal assay when differentiation between fungal and bacterial infections might be desirable. Its multiplexing capacity, detection range, specificity and sensitivity suggest the potential use of this novel MPA-Candida assay in clinical diagnosis and in the control and management of hospital outbreaks.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction/methods*
  12. Oong XY, Ng KT, Lam TT, Pang YK, Chan KG, Hanafi NS, et al.
    PLoS One, 2015;10(8):e0136254.
    PMID: 26313754 DOI: 10.1371/journal.pone.0136254
    Epidemiological and evolutionary dynamics of influenza B Victoria and Yamagata lineages remained poorly understood in the tropical Southeast Asia region, despite causing seasonal outbreaks worldwide. From 2012-2014, nasopharyngeal swab samples collected from outpatients experiencing acute upper respiratory tract infection symptoms in Kuala Lumpur, Malaysia, were screened for influenza viruses using a multiplex RT-PCR assay. Among 2,010/3,935 (51.1%) patients infected with at least one respiratory virus, 287 (14.3%) and 183 (9.1%) samples were tested positive for influenza A and B viruses, respectively. Influenza-positive cases correlate significantly with meteorological factors-total amount of rainfall, relative humidity, number of rain days, ground temperature and particulate matter (PM10). Phylogenetic reconstruction of haemagglutinin (HA) gene from 168 influenza B viruses grouped them into Yamagata Clade 3 (65, 38.7%), Yamagata Clade 2 (48, 28.6%) and Victoria Clade 1 (55, 32.7%). With neuraminidase (NA) phylogeny, 30 intra-clade (29 within Yamagata Clade 3, 1 within Victoria Clade 1) and 1 inter-clade (Yamagata Clade 2-HA/Yamagata Clade 3-NA) reassortants were identified. Study of virus temporal dynamics revealed a lineage shift from Victoria to Yamagata (2012-2013), and a clade shift from Yamagata Clade 2 to Clade 3 (2013-2014). Yamagata Clade 3 predominating in 2014 consisted of intra-clade reassortants that were closely related to a recent WHO vaccine candidate strain (B/Phuket/3073/2013), with the reassortment event occurred approximately 2 years ago based on Bayesian molecular clock estimation. Malaysian Victoria Clade 1 viruses carried H274Y substitution in the active site of neuraminidase, which confers resistance to oseltamivir. Statistical analyses on clinical and demographic data showed Yamagata-infected patients were older and more likely to experience headache while Victoria-infected patients were more likely to experience nasal congestion and sore throat. This study describes the evolution of influenza B viruses in Malaysia and highlights the importance of continuous surveillance for better vaccination policy in this region.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction
  13. Nithya R, Ahmed SA, Hoe CH, Gopinath SC, Citartan M, Chinni SV, et al.
    PLoS One, 2015;10(3):e0118668.
    PMID: 25774907 DOI: 10.1371/journal.pone.0118668
    Salmonellosis, a communicable disease caused by members of the Salmonella species, transmitted to humans through contaminated food or water. It is of paramount importance, to generate accurate detection methods for discriminating the various Salmonella species that cause severe infection in humans, including S. Typhi and S. Paratyphi A. Here, we formulated a strategy of detection and differentiation of salmonellosis by a multiplex polymerase chain reaction assay using S. Typhi non-protein coding RNA (sRNA) genes. With the designed sequences that specifically detect sRNA genes from S. Typhi and S. Paratyphi A, a detection limit of up to 10 pg was achieved. Moreover, in a stool-seeding experiment with S. Typhi and S. Paratyphi A, we have attained a respective detection limit of 15 and 1.5 CFU/mL. The designed strategy using sRNA genes shown here is comparatively sensitive and specific, suitable for clinical diagnosis and disease surveillance, and sRNAs represent an excellent molecular target for infectious disease.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction/methods*
  14. Ahmed SA, Raabe CA, Cheah HL, Hoe CH, Rozhdestvensky TS, Tang TH
    Am J Trop Med Hyg, 2019 06;100(6):1328-1334.
    PMID: 30963989 DOI: 10.4269/ajtmh.18-0525
    The diarrheal disease "cholera" is caused by Vibrio cholerae, and is primarily confined to endemic regions, mostly in Africa and Asia. It is punctuated by outbreaks and creates severe challenges to public health. The disease-causing strains are most-often members of serogroups O1 and O139. PCR-based methods allow rapid diagnosis of these pathogens, including the identification of their biotypes. However, this necessitates the selection of specific target sequences to differentiate even the closely related biotypes of V. cholerae. Oligonucleotides for selective amplification of small RNA (sRNA) genes that are specific to these V. cholerae subtypes were designed. The resulting multiplex PCR assay was validated using V. cholerae cultures (i.e., 19 V. cholerae and 22 non-V. cholerae isolates) and spiked stool samples. The validation using V. cholerae cultures and spiked stool suspensions revealed detection limits of 10-100 pg DNA per reaction and 1.5 cells/mL suspension, respectively. The multiplex PCR assay that targets sRNA genes for amplification enables the sensitive and specific detection, as well as the differentiation of V. cholerae-O1 classical, O1 El Tor, and O139 biotypes. Most importantly, the assay enables fast and cheaper diagnosis compared with classic culture-based methods.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction*
  15. Kanniappan P, Ahmed SA, Rajasekaram G, Marimuthu C, Ch'ng ES, Lee LP, et al.
    J Cell Mol Med, 2017 10;21(10):2276-2283.
    PMID: 28756649 DOI: 10.1111/jcmm.13148
    Technological advances in RNA biology greatly improved transcriptome profiling during the last two decades. Besides the discovery of many small RNAs (sRNA) that are involved in the physiological and pathophysiological regulation of various cellular circuits, it becomes evident that the corresponding RNA genes might also serve as potential biomarkers to monitor the progression of disease and treatment. sRNA gene candidate npcTB_6715 was previously identified via experimental RNomic (unpublished data), and we report its application as potential biomarker for the detection of Mycobacterium tuberculosis (MTB) in patient samples. For proof of principle, we developed a multiplex PCR assay and report its validation with 500 clinical cultures, positive for Mycobacteria. The analysis revealed 98.9% sensitivity, 96.1% specificity, positive and negative predictive values of 98.6% and 96.8%, respectively. These results underscore the diagnostic value of the sRNA gene as diagnostic marker for the specific detection of MTB in clinical samples. Its successful application and the general ease of PCR-based detection compared to standard bacterial culture techniques might be the first step towards 'point-of-care' diagnostics of Mycobacteria. To the best of our knowledge, this is the first time for the design of diagnostic applications based on sRNA genes, in Mycobacteria.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction/methods
  16. Maran S, Faten SA, Lim SE, Lai KS, Ibrahim WPW, Ankathil R, et al.
    Biomed Res Int, 2020;2020:6945730.
    PMID: 33062692 DOI: 10.1155/2020/6945730
    Background: The 22q11.2 deletion syndrome (22q11.2DS) is the most common form of deletion disorder in humans. Low copy repeats flanking the 22q11.2 region confers a substrate for nonallelic homologous recombination (NAHR) events leading to rearrangements which have been reported to be associated with highly variable and expansive phenotypes. The 22q11.2DS is reported as the most common genetic cause of congenital heart defects (CHDs).

    Methods: A total of 42 patients with congenital heart defects, as confirmed by echocardiography, were recruited. Genetic molecular analysis using a fluorescence in situ hybridization (FISH) technique was conducted as part of routine 22q11.2DS screening, followed by multiplex ligation-dependent probe amplification (MLPA), which serves as a confirmatory test.

    Results: Two of the 42 CHD cases (4.76%) indicated the presence of 22q11.2DS, and interestingly, both cases have conotruncal heart defects. In terms of concordance of techniques used, MLPA is superior since it can detect deletions within the 22q11.2 locus and outside of the typically deleted region (TDR) as well as duplications.

    Conclusion: The incidence of 22q11.2DS among patients with CHD in the east coast of Malaysia is 0.047. MLPA is a scalable and affordable alternative molecular diagnostic method in the screening of 22q11.2DS and can be routinely applied for the diagnosis of deletion syndromes.

    Matched MeSH terms: Multiplex Polymerase Chain Reaction/methods*
  17. Nik Zuraina NMN, Goni MD, Amalina KN, Hasan H, Mohamad S, Suraiya S
    Diagnostics (Basel), 2021 Apr 22;11(5).
    PMID: 33922299 DOI: 10.3390/diagnostics11050753
    A thermostabilized, multiplex polymerase chain reaction (mPCR) assay was developed in this study for the detection of six respiratory bacterial pathogens. Specific primers were designed for an internal amplification control (IAC) and six target sequences from Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, Mycobacterium tuberculosis, and Haemophilus influenzae. The resultant seven-band positive amplification control (PAC) of this heptaplex PCR assay corresponded to 105 base pairs (bp) of IAC, 202 bp of K. pneumoniae, 293 bp of S. aureus, 349 bp of S. pneumoniae, 444 bp of P. aeruginosa, 505 bp of M. tuberculosis, and 582 bp of H. influenzae. Results found that 6% (w/v) of the stabilizer was optimum to preserve the functional conformation of Taq DNA polymerase enzyme. This assay was stable at ambient temperature for at least 6 months. The sensitivity and specificity of this assay were both 100% when testing on the intended target organisms (n = 119) and non-intended species (n = 57). The mPCR assay developed in this study enabled accurate, rapid, and simple detection of six respiratory bacteria.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction
  18. Nik Zuraina NMN, Mohamad S, Hasan H, Goni MD, Suraiya S
    Pathog Glob Health, 2023 Feb;117(1):63-75.
    PMID: 35331083 DOI: 10.1080/20477724.2022.2028378
    Respiratory tract infections (RTIs), including pneumonia and pulmonary tuberculosis, are among the leading causes of death worldwide. The use of accurate diagnostic tests is crucial to initiate proper treatment and therapy to reduce the mortality rates for RTIs. A PCR assay for simultaneous detection of six respiratory bacteria: Haemophilus influenzae, Klebsiella pneumoniae, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pneumoniae, was developed in our lab. The current study aimed to evaluate the performance of this assay along with the retrospective surveillance of respiratory pathogens at a teaching hospital in Kelantan, Malaysia. Leftover sputa (n = 200) from clinical laboratories were collected and undergone DNA template preparation for PCR analysis. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the PCR assay were determined in comparison with the gold standard sputum culture. Overall, the accuracy performance of this assay was 94.67% (95% CI: 90.87% to 97.21%) with sensitivity, specificity, PPV and NPV of 100%, 91.67%, 87.1% and 100%, respectively. Based on the organisms detected from sputa, K. pneumoniae ranked as the top isolate (n = 48), followed by P. aeruginosa (n = 13) and H. influenzae (n = 10). Surveillance among the patients showed that the associations of bacterial positive with gender and means of acquisition were found significant (p values = 0.049 and 0.001, respectively). Besides the promising performance of this ready-to-use molecular-based assay for the rapid detection of selected bacteria pathogens, this study also highlighted significant spread of K. pneumoniae RTIs in the community.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction*
  19. Suali L, Mohammad Salih FA, Ibrahim MY, Jeffree MSB, Thomas FM, Siew Moy F, et al.
    Hemoglobin, 2022 Nov;46(6):317-324.
    PMID: 36815306 DOI: 10.1080/03630269.2023.2169154
    β-thalassemia is a serious public health problem in Sabah due to its high prevalence. This study aimed to investigate the effects of different types of β-globin gene mutations, coinheritance with α-globin gene mutations, XmnI-Gγ, and rs368698783 polymorphisms on the β-thalassemia phenotypes in Sabahan patients. A total of 111 patients were included in this study. The sociodemographic profile of the patients was collected using a semi-structured questionnaire, while clinical data were obtained from their medical records. Gap-PCR, ARMS-PCR, RFLP-PCR, and multiplex PCR were performed to detect β- and α-globin gene mutations, as well as XmnI-Gγ and rs368698783 polymorphisms. Our data show that the high prevalence of β-thalassemia in Sabah is not due to consanguineous marriages (5.4%). A total of six different β-globin gene mutations were detected, with Filipino β°-deletion being the most dominant (87.4%). There were 77.5% homozygous β-thalassemia patients, 16.2% compound heterozygous β-thalassemia patients, and 6.3% β-thalassemia/Hb E patients. Further evaluation on compound heterozygous β-thalassemia and β-thalassemia/Hb E patients found no concomitant α-globin gene mutations and the rs368698783 polymorphism. Furthermore, the XmnI-Gγ (-/+) genotype did not demonstrate a strong impact on the disease phenotype, as only two of five patients in the compound heterozygous β-thalassemia group and two of three patients in the β-thalassemia/Hb E group had a moderate phenotype. Our findings indicate that the severity of the β-thalassemia phenotypes is closely related to the type of β-globin gene mutations but not to the XmnI-Gγ and rs368698783 polymorphisms.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction
  20. Jeshveen, S.S., Chai, L.C., Pui, C.F., Son, R.
    MyJurnal
    The main source of E. coli 0157:H7 is cattle, but recent studies showed high percentage of outbreaks
    contributed by contaminated water. The occurrence of E. coli O157:H7 in environmental water samples poses a potential threat to human health. The aim of this study was to establish a protocol for the detection of the pathogen E. coli O157:H7 and E. coli virulence genes (eaeA, rfbE, hly, stx1, and stx2) in a multiplex PCR protocol using six specific primer pairs. The target genes produced species-specific amplicons at 625 bp, 397 bp, 296 bp, 166 bp, 210 bp and 484 bp for E. coli O157:H7 (fliCh7 gene) and virulence genes (eaeA, rfbE, hly, stx1, and stx2) respectively. The results obtained show that the established PCR protocol is suitable for a rapid and specific analysis of the pathogenic E. coli O157:H7 in environmental water samples for the assessment of microbiological risks.
    Matched MeSH terms: Multiplex Polymerase Chain Reaction
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